Fingerprint Image Enhancement

In the recent years, automatic fingerprint identification technique (AFIT),as a kind of biometrics technology, has been applied the most widely. It mainly includes six phases: preprocessing, enhancement, binarization, thinning, feature extraction and matching. It has been intensively studied in the literatures. In practice, especially the suspects'fingerprint images acquired at crime scenes could not be used for identification directly. It needs some computer processing to make them clear enough to use them. The results gotten by the methods reported in the literatures could not satisfy police needs. So, we intensively studied the methods for fingerprint enhancement and deliver new approaches. The approaches are:(1) In fingerprint enhancement, a novel approach of iteration for fingerprint enhancement based on STFT(Short Time Fourier Transform) was proposed. This method gets much better result than the other existing methods.(2) In fingerprint area mask, a novel approach of fast getting fingerprint area mask based on fingerprint image area equalization was proposed. This method reduces largely computer's computation and makes processing parameters the same to all kind of size image.(3) In fingerprint image binarization, a novel approach of fingerprint image fast binarization based on STFT marginal area pixel threshold was proposed. This method reduces largely computation and gets better result than the other existing methods.Besides, we proposed a advanced method of fingerprint enhancement steps.This paper is divided into six chapters. The first chapter was the brief introduction about our research background and significance, the status in quo of the study in the world, existing problems, our solutions and the innovative methods. In the second chapter, basic concepts about fingerprint recognition and identification were introduced. In the third chapter, some typical fingerprint enhancement methods and our method were introduced. In the fourth chapter, some typical fingerprint binarization and thinning methods as well as our method were introduced. In the fifth chapter, some typical fingerprint segmentation methods and our method were introduced. The final sixth chapter is conclusion and discussion.